Resource oversubscription in computing cloud systems is becoming common in information technology (IT) services. Virtual machines (VMs) are often provisioned to host separate services in the cloud systems. Traditionally, these VMs are provisioned with all of their allocated resources (for example, memory and central processing unit (CPU)) guaranteed in the physical resources. Resource allocation of more than the amount that can be guaranteed by the physical resources, that is, resource oversubscription, allows for more VMs to be hosted on a hypervisor. As VMs often do not consume all of the allocated resources, over-subscription can increase resource utilization, and as a result, reduce cost of service provision.
However, oversubscription brings the risk of resource overload in the hypervisor before hosted VMs use up the allocated resources, and the resource overload, especially memory overload, largely degrades service performance.
Existing approaches attempting to remedy the undesirable consequences of oversubscription include migration-only solutions. However, migration-only solutions are not sufficient to remediate overload in over-committed systems (in these systems, there exists the possibility for a large number of hypervisors to be close-to-overload at the same time), and migration overhead may be large in a dense over-committed hypervisor cluster.
Accordingly, a need exists for remediating an overload in over-committed computing environments.